1. Field of the Invention
The present invention relates to a tape feeding apparatus incorporated with a tape clamping mechanism used in, for example, tape bonding machines.
2. Prior Art
In conventional tape clamping mechanisms, an upper clamper (also called the "bonding guide") is positionally fixed, and a bonding tape is clamped by an up and down movement of the lower clamper only. This is described, for example, in Japanese Patent Application Publication (Kokoku) No. 2-1372 and Japanese Patent Application Laid-Open (Kokai) No. 2-273949.
Generally, tab tapes used in the manufacture of semiconductor devices are formed with a copper foil pasted to the surface of a resin tape that has a thickness of approximately 50 to 125 microns. Accordingly, extremely large amounts of warping, torsion and undulation, etc. tend to occur. As a result, in the bonding areas where semiconductor pellets or bumps, etc. are bonded to the tape, it is necessary to apply a certain amount of tension to the tape so that the tape is kept almost flat when the bonding and feeding of the tape are performed.
However, since in the prior art described above the tape is fed with tension applied and is in contact with the upper clamper, rubbing scratches, etc. are occasionally formed on the upper surface of the tape during this feeding operation. In addition, though the upper surfaces of semiconductor pellets or bumps are bonded to the undersurface of the tape, bonding in the prior art is performed with the upper surface of the tape positioned against the undersurface of the upper clamper. In other words, the tape positioning in the prior art is made with reference to the upper surface thereof and not the undersurface. Accordingly, bonding quality tends to be poor.